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Showing papers on "Schottky diode published in 2003"


Journal ArticleDOI
Ali Javey1, Jing Guo2, Qian Wang1, Mark Lundstrom2, Hongjie Dai1 
07 Aug 2003-Nature
TL;DR: It is shown that contacting semiconducting single-walled nanotubes by palladium, a noble metal with high work function and good wetting interactions with nanotube, greatly reduces or eliminates the barriers for transport through the valence band of nanot tubes.
Abstract: A common feature of the single-walled carbon-nanotube field-effect transistors fabricated to date has been the presence of a Schottky barrier at the nanotube–metal junctions1,2,3. These energy barriers severely limit transistor conductance in the ‘ON’ state, and reduce the current delivery capability—a key determinant of device performance. Here we show that contacting semiconducting single-walled nanotubes by palladium, a noble metal with high work function and good wetting interactions with nanotubes, greatly reduces or eliminates the barriers for transport through the valence band of nanotubes. In situ modification of the electrode work function by hydrogen is carried out to shed light on the nature of the contacts. With Pd contacts, the ‘ON’ states of semiconducting nanotubes can behave like ohmically contacted ballistic metallic tubes, exhibiting room-temperature conductance near the ballistic transport limit of 4e2/h (refs 4–6), high current-carrying capability (∼25 µA per tube), and Fabry–Perot interferences5 at low temperatures. Under high voltage operation, the current saturation appears to be set by backscattering of the charge carriers by optical phonons. High-performance ballistic nanotube field-effect transistors with zero or slightly negative Schottky barriers are thus realized.

3,126 citations


Journal ArticleDOI
02 May 2003-Science
TL;DR: Electrical measurements show that the observed optical emission originates from radiative recombination of electrons and holes that are simultaneously injected into the undoped nanotubes, consistent with a nanotube FET model in which thin Schottky barriers form at the source and drain contacts.
Abstract: Polarized infrared optical emission was observed from a carbon nanotube ambipolar field-effect transistor (FET). An effective forward-biased p-n junction, without chemical dopants, was created in the nanotube by appropriately biasing the nanotube device. Electrical measurements show that the observed optical emission originates from radiative recombination of electrons and holes that are simultaneously injected into the undoped nanotube. These observations are consistent with a nanotube FET model in which thin Schottky barriers form at the source and drain contacts. This arrangement is a novel optical recombination radiation source in which the electrons and holes are injected into a nearly field-free region. Sucha source may form the basis for ultrasmall integrated photonic devices.

926 citations


Journal ArticleDOI
TL;DR: A novel fully integrated passive transponder IC with 4.5- or 9.25-m reading distance at 500-mW ERP or 4-W EIRP base-station transmit power, operating in the 868/915-MHz ISM band with an antenna gain less than -0.5 dB.
Abstract: This paper presents a novel fully integrated passive transponder IC with 4.5- or 9.25-m reading distance at 500-mW ERP or 4-W EIRP base-station transmit power, respectively, operating in the 868/915-MHz ISM band with an antenna gain less than -0.5 dB. Apart from the printed antenna, there are no external components. The IC is implemented in a 0.5-/spl mu/m digital two-poly two-metal digital CMOS technology with EEPROM and Schottky diodes. The IC's power supply is taken from the energy of the received RF electromagnetic field with help of a Schottky diode voltage multiplier. The IC includes dc power supply generation, phase shift keying backscatter modulator, pulse width modulation demodulator, EEPROM, and logic circuitry including some finite state machines handling the protocol used for wireless write and read access to the IC's EEPROM and for the anticollision procedure. The IC outperforms other reported radio-frequency identification ICs by a factor of three in terms of required receive power level for a given base-station transmit power and tag antenna gain.

875 citations


Journal ArticleDOI
06 Feb 2003-Nature
TL;DR: A multilayer photovoltaic device structure in which photon absorption instead occurs in photoreceptors deposited on the surface of an ultrathin metal–semiconductor junction Schottky diode is reported, which might provide the basis for durable low-cost solar cells using a variety of materials.
Abstract: There has been an active search for cost-effective photovoltaic devices since the development of the first solar cells in the 1950s (refs 1-3). In conventional solid-state solar cells, electron-hole pairs are created by light absorption in a semiconductor, with charge separation and collection accomplished under the influence of electric fields within the semiconductor. Here we report a multilayer photovoltaic device structure in which photon absorption instead occurs in photoreceptors deposited on the surface of an ultrathin metal-semiconductor junction Schottky diode. Photoexcited electrons are transferred to the metal and travel ballistically to--and over--the Schottky barrier, so providing the photocurrent output. Low-energy (approximately 1 eV) electrons have surprisingly long ballistic path lengths in noble metals, allowing a large fraction of the electrons to be collected. Unlike conventional cells, the semiconductor in this device serves only for majority charge transport and separation. Devices fabricated using a fluorescein photoreceptor on an Au/TiO2/Ti multilayer structure had typical open-circuit photovoltages of 600-800 mV and short-circuit photocurrents of 10-18 micro A cm(-2) under 100 mW cm(-2) visible band illumination: the internal quantum efficiency (electrons measured per photon absorbed) was 10 per cent. This alternative approach to photovoltaic energy conversion might provide the basis for durable low-cost solar cells using a variety of materials.

394 citations


Journal ArticleDOI
TL;DR: In this article, the reverse bias current-voltage measurements of ∼100-μm-diameter gold Schottky contacts deposited on n-type ZnO(0001) wafers and those exposed for 30 min to a remote 20% O2/80% He plasma at 525±20 C and cooled either in vacuum from 425 °C or the unignited plasma gas have been determined.
Abstract: Reverse bias current–voltage measurements of ∼100-μm-diameter gold Schottky contacts deposited on as-received, n-type ZnO(0001) wafers and those exposed for 30 min to a remote 20% O2/80% He plasma at 525±20 °C and cooled either in vacuum from 425 °C or the unignited plasma gas have been determined. Plasma cleaning resulted in highly ordered, stoichiometric, and smooth surfaces. Contacts on as-received material showed μA leakage currents and ideality factors >2. Contacts on plasma-cleaned wafers cooled in vacuum showed ∼36±1 nA leakage current to −4 V, a barrier height of 0.67±0.05 eV, and an ideality factor of 1.86±0.05. Cooling in the unignited plasma gas coupled with a 30 s exposure to the plasma at room temperature resulted in decreases in these parameters to ∼20 pA to −7 V, 0.60±0.05 eV, and 1.03±0.05, respectively. Differences in the measured and theoretical barrier heights indicate interface states. (0001) and (0001) are used in this letter to designate the polar zinc- and oxygen-terminated surfac...

385 citations


Journal ArticleDOI
TL;DR: In this article, the authors report on fabrication and electrical characteristics of ZnO nanorod Schottky diode arrays using noncatalytic metalorganic vapor phase epitaxy.
Abstract: We report on fabrication and electrical characteristics of ZnO nanorod Schottky diode arrays. High quality ZnO nanorods were grown for the fabrication of the Schottky diodes using noncatalytic metalorganic vapor phase epitaxy and Au was evaporated on the tips of the vertically well-aligned ZnO nanorods. I–V characteristics of both bare ZnO and Au/ZnO heterostructure nanorod arrays were measured using current-sensing atomic force microscopy. Although both nanorods exhibited nonlinear and asymmetric I–V characteristic curves, Au/ZnO heterostructure nanorods demonstrated much improved electrical characteristics: the reverse-bias breakdown voltage was improved from −3 to −8 V by capping a Au layer on the nanorod tips. The origin of the enhanced electrical characteristics for the heterostructure nanorods is suggested.

353 citations


Journal ArticleDOI
TL;DR: In this paper, the electrical characterization of nickel silicide Schottky contacts on silicon carbide (4H-SiC) was reported, and the Tung's model was used to determine the Richardson's constant A**.
Abstract: The electrical characterization of nickel silicide Schottky contacts on silicon carbide (4H–SiC) is reported in this article. In spite of the nearly ideal behavior of the contact at room temperature (n=1.05), the electrical behavior monitored in a wide temperature range exhibited a deviation from the ideality at lower temperatures, thus suggesting that an inhomogeneous barrier has actually formed. A description of the experimental results by the Tung’s model, i.e., considering an effective area of the inhomogeneous contact, provided a procedure for a correct determination of the Richardson’s constant A**. An effective area lower than the geometric area of the diode is responsible for the commonly observed discrepancy in the experimental values of A** from its theoretical value in silicon carbide. The same method was applied to Ti/4H–SiC contacts.

222 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the mechanisms of drain current collapse and gate leakage currents in the AlGaN/GaN heterostructure field effect transistor (HFET), and detailed electrical properties of the ungated and Schottky-gated portion of the device were investigated separately.
Abstract: In order to clarify the mechanisms of drain current collapse and gate leakage currents in the AlGaN/GaN heterostructure field effect transistor (HFET), detailed electrical properties of the ungated portion and Schottky-gated portion of the device were investigated separately, using a gateless HFET structure and an AlGaN Schottky diode structure. The gateless device was subjected to plasma treatments and surface passivation processes including our novel Al2O3-based surface passivation. dc I–V curves of gateless HFETs were highly nonlinear due to virtual gating by surface states. After drain stress, air-exposed, H2 plasma-treated and SiO2-deposited gateless HFETs showed an initial large-amplitude exponential current transient followed by a subsequent smaller, slow, and highly nonexponential response. The former was explained by emission from deep donors at Ec−0.37 eV, and the latter by emission from surface states. Capture transients with stress-dependent capture barriers were also observed. An x-ray photoe...

209 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of the interfacial oxide layer and the ideality factor n in the current transport mechanism of MIS diodes was investigated and the energy distribution of Nss was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height.
Abstract: In order to good interpret the experimentally observed non-ideal Al/SnO2/p-Si (MIS) Schottky diode parameters such as the barrier height ΦB, series resistance Rs and density of interface states Nss, a calculation method has been reported by taking into account interfacial oxide layer and ideality factor n in the current transport mechanism. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of MIS diodes are studied over a wide temperature range of 80–350 K. The effects of Rs, interfacial layer and Nss on I–V and C–V characteristics are investigated. The values of n were strongly temperature dependent and decreased with increasing temperature. The energy distribution of Nss was determined from the forward bias I–V characteristics by taking into account the bias dependence of the effective barrier height. The mean Nss estimated from I–V and C–V measurements decreased with increasing temperature. The Rs estimated from Cheung’s functions was strongly temperature dependent and decreased with increasing temperature. The I–V characteristics confirmed that the distribution of Nss, Rs and interfacial layer are important parameters that influence the electrical characteristics of MIS devices.

195 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used microwave plasma chemical vapour deposition to grow epitaxial diamond layers with low boron doping, from 5 × 1014 to 1 × 1016 cm−3, and the compensating n-type impurities are the lowest reported for any semiconducting diamond, 700 °C for 1 s in air.
Abstract: Exceptionally pure epitaxial diamond layers have been grown by microwave plasma chemical vapour deposition, which have low boron doping, from 5 × 1014 to 1 × 1016 cm−3, and the compensating n-type impurities are the lowest reported for any semiconducting diamond, 700 °C for ~1 s in air. Schottky diodes made on these epitaxial diamond films have breakdown voltages >6 kV, twelve times the highest breakdown voltage reported for any diamond diode and higher than any other semiconductor Schottky diode.

184 citations


Journal ArticleDOI
TL;DR: Au and Ag Schottky contacts on the epiready (0001)Zn surface of bulk n-ZnO crystals show Schotty barrier heights of 0.65-0.70 eV from capacitance-voltage measurements, activation energies for reverse saturation currents of 0 3 −0.4 eV and saturation current densities ranging from 10−5 A cm−2 on surfaces etched in HCl to 8×10−7 A¾2 on solvent cleaned samples.
Abstract: Au and Ag Schottky contacts on the epiready (0001)Zn surface of bulk n-ZnO crystals show Schottky barrier heights of 0.65–0.70 eV from capacitance–voltage measurements, activation energies for reverse saturation currents of 0.3–0.4 eV and saturation current densities ranging from 10−5 A cm−2 on surfaces etched in HCl to 8×10−7 A cm−2 on solvent cleaned samples. The diode ideality factors were in the range 1.6–1.8 under all conditions. The properties of both the Au and the Ag Schottky diodes were degraded by heating in vacuum to temperatures even as low as 365 K. The degradation mechanisms during annealing were different in each case, with the Au showing reaction with the ZnO surface and the Ag contacts showing localized delamination. Mechanical polishing of the ZnO surface prior to contact deposition produced a high-resistivity damaged layer with prominent deep level defects present with activation energies of 0.55 and 0.65 eV.

Patent
Sei-Hyung Ryu1
24 Apr 2003
TL;DR: The Schottky diode may have an active area less than the active area of a built-in body diode of the DMOSFET as mentioned in this paper, and it may have a turn-on voltage lower than that of the body diodes.
Abstract: Silicon carbide semiconductor devices and methods of fabricating silicon carbide semiconductor devices have a silicon carbide DMOSFET and an integral silicon carbide Schottky diode configured to at least partially bypass a built in diode of the DMOSFET. The Schottky diode may be a junction barrier Schottky diode and may have a turn-on voltage lower than a turn-on voltage of a built-in body diode of the DMOSFET. The Schottky diode may have an active area less than an active area of the DMOSFET.

Patent
14 Jan 2003
TL;DR: In this paper, the Fermi level of the semiconductor channel is depinned in a region near the junction and the junction has a specific contact resistance of less than approximately 1000 Ω-μm 2.
Abstract: A transistor includes a semiconductor channel disposed nearby a gate and in an electrical path between a source and a drain, wherein the channel and at least one of the source or the drain are separated by an interface layer so as to form a channel-interface layer-source/drain junction in which a Fermi level of the semiconductor channel is depinned in a region near the junction and the junction has a specific contact resistance of less than approximately 1000 Ω-μm 2 . The interface layer may include a passivating material such as a nitride, a fluoride, an oxide, an oxynitride, a hydride and/or an arsenide of the semiconductor of the channel. In some cases, the interface layer consists essentially of a monolayer configured to depin the Fermi level of the semiconductor of the channel, or an amount of passivation material sufficient to terminate all or a sufficient number of dangling bonds of the semiconductor channel to achieve chemical stability of the surface. Also, the interface layer may include a separation layer of a material different than the passivating material. Where used, the separation layer has a thickness sufficient to reduce effects of metal-induced gap states in the semiconductor channel.

Journal ArticleDOI
TL;DR: In this paper, the first 4H-SiC Schottky barrier diode (SBD) blocking over 10 kV was demonstrated using 115-spl mu/m n-type epilayers doped to 5.6 /spl times/ 10/sup 14/ cm/sup -3/ through the use of a multistep junction termination extension.
Abstract: This letter reports the demonstration of the first 4H-SiC Schottky barrier diode (SBD) blocking over 10 kV based on 115-/spl mu/m n-type epilayers doped to 5.6 /spl times/ 10/sup 14/ cm/sup -3/ through the use of a multistep junction termination extension. The blocking voltage substantially surpasses the former 4H-SiC SBD record of 4.9 kV. A current density of 48 A/cm/sup 2/ is achieved with a forward voltage drop of 6 V. The Schottky barrier height, ideality factor, and electron mobility for this very thick epilayer are reported. The SBD's specific-on resistance is also reported.

Journal ArticleDOI
TL;DR: In this paper, the hydrogen response of Pd:GaN Schottky diodes, prepared by in situ and ex situ deposition of catalytic Pd-Schottky contacts on Si-doped GaN layers is compared.
Abstract: The hydrogen response of Pd:GaN Schottky diodes, prepared by in situ and ex situ deposition of catalytic Pd Schottky contacts on Si-doped GaN layers is compared. Ex situ fabricated devices show a sensitivity towards molecular hydrogen, which is about 50 times higher than for in situ deposited diodes. From the analysis of these results, we conclude that adsorption sites for atomic hydrogen in Pd:GaN sensors are provided by an oxidic intermediate layer. In addition, in situ deposited Pd Schottky contacts reveal lower barrier heights and drastically higher reverse currents. We suggest that the passivation of the GaN surface before ex situ deposition of Pd also results in quenching of leakage paths caused by structural defects.

Journal ArticleDOI
TL;DR: In this paper, commercial Si pn and SiC Schottky diodes are tested and characterized, their behavioral static and loss models are derived at different temperatures, and they are compared with respect to each other.
Abstract: The emergence of silicon carbide (SiC) based power semiconductor switches, with their superior features compared with silicon (Si) based switches, has resulted in substantial improvement in the performance of power electronics converter systems. These systems with SiC power devices have the qualities of being more compact, lighter, and more efficient; thus, they are ideal for high-voltage power electronics applications. In this study, commercial Si pn and SiC Schottky diodes are tested and characterized, their behavioral static and loss models are derived at different temperatures, and they are compared with respect to each other.

Patent
04 Aug 2003
TL;DR: A semiconductor device including a schottky device and a trench type semiconductor switching device such as a MOSFET formed in a common die as mentioned in this paper is an example of such a device.
Abstract: A semiconductor device including a schottky device and a trench type semiconductor switching device such as a MOSFET formed in a common die.

Journal ArticleDOI
TL;DR: In this article, a GaN LED with a Schottky diode was shown to increase the electrostatic discharge threshold from 450 to 1300 V. Although the reverse current and the forward turn-on voltage were both higher for the GaN LEDs with the diode.
Abstract: GaN Schottky diodes were built internally inside the GaN green LEDs by using etching and redeposition techniques. By properly selecting the etching areas underneath the bonding pads, one can minimize the optical loss due to the etching process. Although the reverse current and the forward turn-on voltage were both higher for the GaN LED with a Schottky diode, it was found that the internal Schottky diode could significantly increase the electrostatic discharge threshold from 450 to 1300 V.

Journal ArticleDOI
TL;DR: In this article, the effect of high-energy radiation exposure on device characteristics is discussed taking into account possible contact inhomogeneities arising from dislocations and interfacial defects, and the effects observed in the Schottky diode I-V and C-V characteristics indicate that the total-dose radiation hardness of GaN devices may be limited by susceptibility of the metal-GaN interface to radiation-induced damage.
Abstract: The effect of /spl gamma/-ray exposure on the electrical characteristics of nickel/n-GaN Schottky barrier diodes has been investigated using current-voltage (I-V), capacitance-voltage (C-V), and deep-level transient spectroscopy (DLTS) measurements. The results indicate that /spl gamma/-irradiation induces an increase in the effective Schottky barrier height extracted from C-V measurements. Increasing radiation dose was found to degrade the reverse leakage current, whereas its effect on the forward I-V characteristics was negligible. Low temperature (/spl les/50) post-irradiation annealing after a cumulative irradiation dose of 21 Mrad(Si) was found to restore the reverse I-V characteristics to pre-irradiation levels without significantly affecting the radiation-induced changes in C-V and forward I-V characteristics. Three shallow radiation-induced defect centers with thermal activation energies of 88 104 and 144 meV were detected by DLTS with a combined production rate of 2.12 /spl times/ 10/sup -3/ cm/sup -1/. These centers are likely to be related to nitrogen-vacancies. The effect of high-energy radiation exposure on device characteristics is discussed taking into account possible contact inhomogeneities arising from dislocations and interfacial defects. The DLTS results indicate that GaN has an intrinsically low susceptibility to radiation-induced material degradation, yet the effects observed in the Schottky diode I-V and C-V characteristics indicate that the total-dose radiation hardness of GaN devices may be limited by susceptibility of the metal-GaN interface to radiation-induced damage.

Journal ArticleDOI
TL;DR: In this article, the barrier heights of Ir, Ni, and Re Schottky contacts on strained Al0.25Ga0.75N/GaN heterostructures were characterized using capacitance-voltage (C-V) and I-V techniques.
Abstract: Ir, Ni, and Re Schottky contacts on strained Al0.25Ga0.75N/GaN heterostructures are characterized using capacitance–voltage (C–V) and I–V techniques. Based on the measured C–V characteristics, two dimensional electron gas sheet carrier concentrations at the AlGaN/GaN interface and barrier heights of Ir, Ni, and Re Schottky contacts are calculated. The barrier heights of 1.12, 1.27, and 1.68 eV are obtained for Ir, Ni, and Re Schottky contacts, respectively. The results show that the barrier heights of Schottky contacts on strained AlGaN/GaN heterostructures are strongly dependent on the metal work functions. However, contrary to Schottky contacts on bulk AlGaN or GaN, the barrier height on strained AlGaN/GaN heterostructures is lower for a Schottky contact with a higher metal work function. This is attributed to the stronger wave function coupling between electrons in the Schottky metal and surface donor electrons. The I–V characteristics for Ir, Ni, and Re Schottky contacts confirm the results obtained b...

Journal ArticleDOI
TL;DR: In this article, an AlGaN/GaN heterojunction field effect transistor (HFET) with a very low on-state resistance was fabricated on a sapphire substrate using gas-source molecular beam epitaxy.
Abstract: We fabricated an AlGaN/GaN heterojunction field effect transistor (HFET) with a very low on-state resistance. An undoped Al0.2Ga0.8N(30 nm)/GaN(2 μm) heterostructure was grown on a sapphire substrate using gas-source molecular-beam epitaxy. The undoped GaN layer had a high resistivity (above 10 M Ω ) and the breakdown field of the undoped layer was about 2 MV/cm. Si-doped GaN with a carrier concentration of 5×1019 cm−3 was selectively grown in the source and drain regions for obtaining a very low contact resistance. As a result, a very low ohmic below 1×10−7 Ω cm2 was obtained. After that, an Al0.2Ga0.8N/GaN HFET was fabricated. The gate width was 20 cm and the gate length was 2 μm. The ohmic electrode materials were Al/Ti/Au and the Schottky electrodes were Pt/Au. The distance between the source and the drain was 13 μm. The HFET was operated at a current of over 20 A. A higher switching speed of HFET was obtained.

Journal ArticleDOI
Jin-Ping Ao1, Daigo Kikuta1, Naotaka Kubota1, Yoshiki Naoi1, Yasuo Ohno1 
TL;DR: In this article, a copper gate AlGaN/GaN high electron mobility transistors (HEMTs) with low gate leakage current was demonstrated, and the Schottky barrier height of Cu on n-GaN was 0.18 eV higher than that of Ni/Au.
Abstract: Copper (Cu) gate AlGaN/GaN high electron mobility transistors (HEMTs) with low gate leakage current were demonstrated. For comparison, nickel/gold (Ni/Au) gate devices were also fabricated with the same process conditions except the gate metals. Comparable extrinsic transconductance was obtained for the two kinds of devices. At gate voltage of -15 V, typical gate leakage currents are found to be as low as 3.5/spl times/10/sup -8/ A for a Cu-gate device with gate length of 2 /spl mu/m and width of 50 /spl mu/m, which is much lower than that of Ni/Au-gate device. No adhesion problem occurred during these experiments. Gate resistance of Cu-gate is found to be about 60% as that of NiAu. The Schottky barrier height of Cu on n-GaN is 0.18 eV higher than that of Ni/Au obtained from Schottky diode experiments. No Cu diffusion was found at the Cu and AlGaN interface by secondary ion mass spectrometry determination. These results indicate that copper is a promising candidate as gate metallization for high-performance power AlGaN/GaN HEMT.

Journal ArticleDOI
TL;DR: In this article, the effects of surface preparation and thermal annealing on the Ni/6H-SiC Schottky barrier height were studied by monitoring the forward I-V characteristics of Schotty diodes, and the ideality factor n and the barrier height ΦB were found strongly dependent on the impurity species present at the metal/SiC interface.
Abstract: In this work, the effects of surface preparation and thermal annealing on the Ni/6H-SiC Schottky barrier height were studied by monitoring the forward I–V characteristics of Schottky diodes. The ideality factor n and the barrier height ΦB were found to be strongly dependent on the impurity species present at the metal/SiC interface. The physical mechanism which rules the Schottky barrier formation is discussed by considering the nature of the impurities left from the different surface preparation methods prior to metal deposition. In contrast, nickel silicide/SiC rectifiers (Ni2Si/6H-SiC), formed by thermal reaction of Ni/6H-SiC above 600 °C, have an almost ideal I–V curve, independent of the surface preparation. Further improvement in the barrier height distribution can be obtained by increasing the annealing temperature to 950 °C. This behaviour is discussed in terms of the silicide phases and the consumption of a SiC layer during the thermal reaction.

Journal ArticleDOI
TL;DR: In this article, the frequency-dependent properties of organic diodes with a pentacene/aluminum Sckottky contact have been investigated, and it was revealed that the frequency dependent properties are related to the localized traps in the band gap of pentaene.

Journal ArticleDOI
TL;DR: In this article, the effects of inductively coupled plasma (ICP) etching on electrical properties of n-type GaN Schottky contacts were investigated by observing ion damage using deep-level transient spectroscopy.
Abstract: The effects of inductively coupled plasma (ICP) etching on electrical properties of n-type GaN Schottky contacts were investigated by observing ion damage using deep-level transient spectroscopy. An electron trap, not previously seen, localized near the contact, as well as a pre-existing trap, was observed in the ICP-etched sample. The ICP-etched surface was found to be N-deficient, which means that N vacancies (VN) were produced by ICP etching. From these, the origin of the ICP-induced electron trap was suggested to be VN or a VN-related complex of point defects. The ICP-induced traps provided a path for the transport of electrons, leading to the reduction of Schottky barrier height and increase of gate leakage current.

BookDOI
Mike Golio1
01 Feb 2003
TL;DR: Golio et al. as discussed by the authors proposed a nonlinear Transistor Modeling for Circuit Simulation (NTMS) for circuit simulation, and demonstrated the nonlinear transistor model with high voltage and low power.
Abstract: Varactors, Jan Stake Schottky Diode Frequency Multipliers, Jack East Transit Time Microwave Devices, Robert J. Trew Bipolar Junction Transistors, John C. Cowles Heterostructure Bipolar Transistors, William Liu Metal-Oxide-Semiconductor Field Effect Transistors, Leonard MacEachern, Tajinder Manku Metal Semiconductor Field Effect Transistors, Michael S. Shur High Electron Mobility Transistors, Prashant Chavarkar, Umesh Mishra RF Power Transistors from Wide Bandgap Materials, Karen E. Moore Monolithic Microwave IC Technology, Lawrence P. Dunleavy Semiconductors, Mike Harris Metals, Mike Golio RF Package Design and Development, Jeanne S. Pavio Thermal Analysis and Design of Electronic Systems, Avram Bar-Cohen, Karl J. Geisler, Allan D. Krauss Low Voltage/Low Power Microwave Electronics, Mike Golio Technology Computer Aided Design, Peter A. Blakey Nonlinear Transistor Modeling for Circuit Simulation, Walter R. Curtice

Journal ArticleDOI
TL;DR: In this article, a Schottky contact is integrated into every cell of the VDMOSFET to improve the high-voltage vertical double-diffused MOS-FET body-diode recovery speed, which shows a 50% decrease in the reverse recovery charge and a 60% increase in the softness factor of the body diode.
Abstract: A new approach to improve the high-voltage vertical double-diffused MOSFET (VDMOSFET) body-diode recovery speed is proposed. In this approach, a Schottky contact is integrated into every cell of the VDMOSFET. Experimental results from the fabricated samples show a 50% decrease in the reverse recovery charge and a 60% increase in the softness factor of the body diode in 500 V/2 A VDMOSFETs.

Proceedings ArticleDOI
16 Sep 2003
TL;DR: In this article, NiSi SALICIDE has been integrated with sub-50 nm gate length transistors and compared to its CoSi/sub 2/ counterpart, and it was found that NiSi layers basic lattice planes with vertical orientation are often observed inside the grains.
Abstract: In this work, NiSi SALICIDE has been fully integrated with sub-50 nm gate length transistors and compared to its CoSi/sub 2/ counterpart. Nickel thickness has been reduced to target the CoSi/sub 2/ sheet resistance. It was found that NiSi layers basic lattice planes with vertical orientation are often observed inside the grains. NiSi-based CMOS transistors show the same performance as CoSi2-transistors, but nickel can also silicide very narrow poly lines whereas cobalt can not. Moreover, NiSi reduces the STI diode-leakage perimeter, but increases channel side leakage, where CoSi/sub 2/ shows a "Schottky behavior". Thus we show that nickel allow MOS transistor scaling for future technology.

Proceedings ArticleDOI
19 Feb 2003
TL;DR: In this paper, a 1 MHz hard-switched DC/DC converter employing SiC JFETs and Schottky diodes is presented, which was designed to convert 270 Vdc to 42 Vdc such as may be needed in future electric cars.
Abstract: Silicon carbide (SiC) is a wide bandgap semiconductor material that offers performance improvements over silicon (Si) for power semiconductors with accompanying benefits for power electronics applications that use these semiconductors. The wide bandgap of SiC results in higher junction forward voltage drops, so SiC is best suited for majority carrier devices such as FETs and Schottky diodes. The wide bandgap of SiC results in it having a high breakdown electric field, which in turn results in lower resistivity and narrower drift regions in power devices. This dramatically lowers the resistance of the drift region and means that SiC devices with substantially less area than their corresponding Si devices can be used. The lower device area reduces the capacitance of the devices enabling higher frequency operation. Here the results from a 1 MHz hard-switched DC/DC converter employing SiC JFETs and Schottky diodes are presented. This converter was designed to convert 270 Vdc to 42 Vdc such as may be needed in future electric cars. The results provide the performance obtained at 1 MHz and demonstrate the feasibility of a hard-switched DC/DC converter operating at this frequency.

Journal ArticleDOI
TL;DR: The transition from Schottky to ohmic contact in the nickel silicide/SiC system during annealing from 600 to 950 °C was investigated by measuring the electrical properties of the contact and by analyzing the microstructure of the silicide and SiC interface as mentioned in this paper.